A system of measurement for the internal bore diameter of a rifled-barreled firearm (rifle or pistol).

Carbine

"A carbine is a firearm similar to a rifle or musket. Many carbines, especially modern designs, were developed from rifles, being essentially shortened versions of full rifles firing the same ammunition, although often at a lower velocity. The shorter length and lighter weight of carbines makes them easier to handle in close-quarter situations, or when deploying from vehicles. The disadvantages of carbines are generally poorer long-range accuracy and shorter effective range.
"

Cartridge

"A small usually cylindrical packet, containing a detonating primer, a powder charge, a load -- either a single projectile for a rifle or a quantity of small pellets for a shotgun -- and possibly some attendant wadding.
"

Case

The envelope (container) of a cartridge. For rifles and handguns it is usually of brass or other metal; for shotguns it is usually of paper or plastic with a metal head and is more often called a "shell."

Casehardening

"Mottled blue/green/brown colors on a shotgun or double rifle receiver, the by-product of a heat-treating process that incorporates carbon into the surface molecular structure of the steel, providing a hard-wearing surface without making the entire receiver brittle.
"

Centerfire

"A cartridge, or firearm using a cartridge, with the primer in the center of the cartridge base.
"

Cerakote

Cerakote is a Polymer-Ceramic Composite coating that can be applied to metals, plastics, polymers, and wood. The unique formulation used for Cerakote ceramic coating enhances a number of physical performance properties including abrasion/wear resistance, corrosion resistance, chemical resistance, impact strength, and hardness. This state-of-the-art coating technology out-performs any competitive coating in both laboratory settings and real world applications.

Chamber

"An area at the breech end of a barrel, of about the diameter of the cartridge for which the gun was intended, and into which the cartridge is inserted.
"

Checkering

A regular pattern of fine grooves cut into the surface of a stock to aid in gripping a gun.

Cheekpiece

"A broad, flat, raised area on the side of a buttstock.
"

Choke

"A carefully measured constriction of the bore of a shotgun at the muzzle, designed to control the spread of the shot as it leaves the barrel.
"

Choke Tubes

"Short, interchangeable cylinders, of subtly different internal tapers, that screw into a threaded recess at the muzzle of a shotgun.
"

Cocking Indicators

Small devices attached to the internal hammer of a gun and visible from the exterior of the gun to show when gun is cocked and when it has been fired.

Comb

"The top of a gun's stock, where a shooter rests their cheek when mounting a gun.
"

Compensator

A device attached to the muzzle of a firearm to reduce the upward movement of the muzzle brought about by recoil.

Cylinder

"A revolver part, cylindrical in shape, with firing chambers that rotate to align with the bore.
"